Thread-controlling device



June 12, 192s. 1,673,355

A. F. FIFIELD THREAD CONTROLLING DEVI CE Filed May 11, 1926 2 Sheets-Sheet INVENTOR 44M7 0 WITNESSES?) MW ATTORNEY June 12, 1928. A. F. FIFIELD THREAD CONTROLLING DEVI CE Filed May 11, 1926 WITNESgS mm NMWMMI 2 Sheets-Sheet 2 |NVENTOR may a s TTORNEY Patented June 12, 1928.

UNITED STATES 1,673,355 PATENT OFFICE.

ALBERT F. FIFIELD, F NEWARK, NEW JERSEY, ASSIG-NOR TO THE SINGER MANUFAC- TUBING COMPANY, or ELIZABETH, NEW .innsn A conronarron on NEW JERSEY.

THREAD-COI TROLLING DEVICE.

Application filed May 11, 1926. Serial No. 108,233.

This invention relates generally to tack ing and barring machines of the single thread chain stitch rotary looper type for sewing on. buttons and may be embodied in the machine disclosed in my prior Patent No. 1,514,609, dated Nov. 1 1, 192%. In machines of this type, particularly those in which alarge loop of thread is thrown out by the rising needle, due to a long needlebar stroke, it not infrequently happens that the needle-thread loop is reseized by the looper before the thread is drawn up by the take-up to set the stitch.

An object of the present invention is to provide a guard for the needle-thread loop which will prevent reseizure of the loop by the looper before it is drawn up by the take-up.

It'consists preferably of a guard member arranged transversely of and across the plane of movement of the looper beakso as to cover such beak after seizure of the new needle-loop and prevent the old loop from whipping around at either sideof the needle into the path of the looper-beak before it is drawn up bythetake-up. In one form of the improvement the guard-member for the needle thread is carried by the needle-guard secured to the under side of the throat-plate.

The improvement is illustrated in the accompanying drawings in which Fig. 1 is a side elevation, partly in section, of a sewing machine embodying the'invention. Fig. 2 is a bottom plan View on an enlarged scale of the elements upon theunder side of the worlesupport adjacent the sewing point. Fig. 3 is a perspective view of the parts shown in Fig. Fig. elis a sectional elevation of the WUITk'SUpPOIlZ at the sewing point and Fig. is a detailed perspective view of the thread guard.

In the iireferred embodiment of the invention, as illustrated, the sewing machine is constructed with a frame comprising the base or bed 1 from which rises the hollow standard 2 having the overhanging tubular arm 3 extending therefrom and terminating in a head l. Suitably journaled in the tubular arm 3 is the main-shaft 5 carrying at its forward end a cranloarin 6 having a linkconnection 7 with theheedlebar 8 mounted for vertical reciprocation in the head 4: and carrying at its lower end the needle 9.

Journaled in the hollow standard 2 is the vertical shaft 10 geared at 11 to the mainshaft 5 and at 152 to the looper-sl1aft 1.3 cara driving worm 18on the main-shaft 5. The i feed-wheel is formed on its side faces with lateral and longltudinal feed-cam grooves,

shown at 19. The feed-cam grooves are en tered by follower rolls carried by the usual lateral and longitudinal feed-connections with the usual work-clamp carried bythe clamp-supportingbar 2O slidably mounted upon the bed 1. The particular work-olamp herein illustrated is adapted to hold gaiter buttons spaced from the material to which they are attached so as to produce a threadshank around which a thread is wound by hand. i The clamp comprises the usual workseparable button clamping jaws22 having at their. work-engaging faces the blocks 23 for spacing the buttons from the material, and carried, by the overhanging or upper supporting member 24; of the work-clamp, which is spring-pressed toward the work by the usual leaf-spring 25. The upper member of the work-clamp maybe lifted by the usualconnection with a lifter-bar 36 slidably 'journaled in the head 4: adjacent the needle-bar 8. At its upper end the lifting bar is connected to the treadle-controlled the longitudinal feed-cam groove being U supporting plate 21 and upper laterally clamp lifting lever 27 fulcrumed on the bracket 28 which latter is mounted on the bracket-arm 3. I I 7 On the rear end of themain-shaft 5 are mounted the tight and loose pulleys 29, 80, respectively, of a common form of start and stop motion device including the starting and stopping lever 31 which is pivoted at 32 and carries the belt-shipper 33and 'stopping tooth 34, the latter cooperating with the stopping-cam formed on the hub of the tight pulley 29. This stop-motion de vice is more fully disclosed in the patent to W. L. Barron, No. 1,093,241, of Apr. 14, 1914, to which reference may be had. The stop-motion device is titted with the braking device of my prior Patent No. 1,-l98,649, of June .24, 192l,and comprises essentially the brake-arm 36 pivoted to the stop-motion frame at 37 and carrying at its upper end the brake-shoe 38 adapted to bear against the tight pulley 29 under the action of the coil-spring 39.

The machine is also fitted with the threadcontrollingand take-up mechanism of my prior Patent No. 1,452,033, oi Apr. 17, 1923, and comprising essentially the needlebar thread take-up eye 40 cooperating with the thread-post ll on which is slidingly mounted the sp'rinepreased collar -12 beneath which the wiring threat 1 is led from the thread-eye ii; on the bracket 28. The sewing thread (I. is led from the source of supply through the usual intermittent tension device ll, through the lixed eyelets 45, constantte'nsio'n 41-6, and thence tln'ough the tixed eyelet 43 and yielding thread-collar 42 to the needle-bar take-up 4-0 previously n'ientioned. A thrcad-pull-olf bar 47, rigidly mounted upon the upper end ol the t'lilll'lP-ll'lddll' bar 26 is fitted at its free end with thread-engaging hooks -l8 for drawing oil a supply of slack-thread through the open intermittent tension device 44 in the well known manner when the machine is at rest and the work-clamp is raised to release the work.

The machine is also fitted with a threadcutting mechanism comprising; a hel'lcranklever 49 pivoted at 49' upon the under side of the throat-plate 50. The bellcrank-lever has secured thereon a thread-cutting blade .31 and is connected to be operated by means of the usual overthrow side-motion of the stop-lever 31 which gives an en'dwise movement to the link 52 as the main-shaft 5 comes to rest. This well known endwise movement given to the link 52 causes the lever 49 to be swan; about its pivot 49 whereby the threacbcutting blade 51 is caused to enter and sever the lastneedle-loop below the work. Secured upon the underside of the throatdate by the fastening screws 53 is the needle-guard 523 which is disposed above and on that side of the needle remote from the 'looper let so as to effectually guard against. deflection of the needle below the throat-plate and insure seizure o'f the needlethread loop by the looper.

Mounted upon the needle-guard by'one of the fastening screws 53 is the shank a l of the thread-guard having the angularly related walls 5G. 57 so disposed adjacent the top and side of the l0()]')tt"l)Gtll as to guard the latter after passing loop-seizing,

turned portion and the laterally extending: portion 57 with inclined outer edge.

In the operation of sewing machines of this type, it not infrequently happens that the loop of needle-thread alter being cast oil from the looper is deflected in the path of the looper beak and caught a second time by the latter before the take-up has drawn it; up. This may be due to the air currents produced by the rapidly rotating looper or to the twisting of the needle-tlnead loop. in order to overcome this diliiculty the threadguard positioned in rear of the loopcr and out of range of the exnmnding, or nascent needle-loop prior to seizure of such loop by the looper, so that the ell'ectivc front edge 1 of such guard covers the looper-beak shortly after the looper has seized a new ncedle-loop and is shedding the previously seized loop which is drawn upwardly past the edge :1: of the thread-guard above the path of the looper-beak during the action of the take-up.

lVhile in one form of the in'l n'ovement the. thread-guard Si is mounted upon the needleguard 53, it will be readily understood that the thread-guard will be equally effective it mounted upon some other part of the machine adjacent the looper 14, provided it so disposed as to guard the looper-beak after passing loop-seizing position.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine, in combination, a

thread-carrying needle, means for reciprm eating said needle, a rotary chain-stitch looper having a loop-seizing beak and loopspreading wing and cooperating with said needle in the formation of stitches, take-up means, and a guard having its active portions adjacent; the needle disposed in rear of the needle-path and out of range oi the ex panding needle-loop prior to seizure of such loop by the looper, said guard being adapted to cover said looper-beak after it has seized a new needle-loin) and prevent its subsequent seizure of the old or cast-otl' needle-loop bei'ore the latter is drawn up by th takcnp means.

2. In a sewing machine. in combination. a. thread-caruving needle, a rotary chainstitch looper having a loop-z-=eizinebeak and loop-sprtaiding win; and cooperating with said needle in the formation of stitches, take-up means, and a guard havin; angularly related walls disposed in rear of the nee die-path, said walls being disposed respectively adjacent the top and side of the looper-beak after passing loop-seizing position. whereby to guard the loopcr-heak after it ha seized a needle-loop and prevent reseizure of the cast-oft needle-loop before the latter is drawn up by the take-up means.

3. In a sewing machine, in combination. a reciprocating needle, a rotary chain-stitch looper having a loop-seizing beak and loopspreading wing. and a thread-guard having an effective front edge disposed transversely of the plane of movement, of the looperltH) beak and in rear of the needle-path and adapted to cover the looper-beak after it has seized a needledoop and prevent the cast-Ol f neediedeop ii'roin Whipping around in front of the looper-heak.

4'. in a sewing machine, in combination, teething mechanism, :1 thread-earrying needie, a rotary chain-stitch leoper having a imp-seizing beak and loop-spreading Wing end cooperating with said needle in the forniatien of stitches, a needle-guard, take-up means, and a thread-guard carried by the needle-guard and having an active front edge extending transversely of the line of feed in rear of the needle-path for guarding said leoper-heak after it has seized a new needle-100p and preventing reseizure 0f the old or cast-off needledoop before the latter is drawn up by the take-up means.

In testimony whereof, I have signed my name to this specification.

ALBERT F. FIFIELD. 

